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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9bbbdb26d97dac46c0ca06b6229d4fcb310fe549ecf16a4a71b38bc1e0728e1' 
  AND token = '2uZkEmljCRNyhR6jtYrh0JyGTPtqAa69SC5K0v8dGsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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