SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2339f1c8545897fd2c39d0bb4fe6c5c7c3280866b2e2f208eda521e0e6b95d8a' 
  AND token = 'eG/qzuIik9TJRDLfDsY9v2OSkvIWoIK0dGtH9UcSasE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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