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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6ddfcf18b2b5bd0fd6785c941d5dd49a2fe447bfa1c779d7feaa7597143f0a2a' 
  AND token = 'TR5IzPS6ksHnmfPkL9lKMDoaPrm0NvJwQK1Lg/xognI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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