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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0fdbb4fd4a1c0bd7f3af24ef01e10f6d31d9c7e5c7896a73563290d1047ca15' 
  AND token = 'cdTWwlbYY/BrU7gzsbPK9AcL69QKmOFeMygKLSqkF3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}