SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '315958dc419dece4d1c277024cd51c826e46096620d376eecd7ce47b66cf8be6' 
  AND token = '7+zNaSWGZUdegtkjdDclgWHFgUHQkqX7BcsxMTxe6jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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