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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ce36f18f8bc65c7309f970b2f443db783dbb7bda0a4b3b3647a57b391c10b0' 
  AND token = 'Cuh2dVeZyp5zsqWtdPxe7BQrgQ47RjcqUiRUnpsqt/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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