SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd4a2c7a2b2ff0681e685848d710d638468a090cae6935e391b2262957504222' 
  AND token = 'nCtKS4fUc51eBjCkvbzjctQPMkRMToHmiiuf0PxFpOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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