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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51ac8525f3b509ce66718efaea1beb698cd2818a48c1f72a2adc30a050c1c7d0' 
  AND token = 'QrwEYwpUEgisRq1EgwNrZ948ndB+uIDR0Vb1PH+QKsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}