SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46e8e180b7e518575c253495c8971976f7fb475f515ea16d2162aff5200d8cb5' 
  AND token = '0YMqcCmgoLItYxbUea8ah7q5PJehkEvGFFU2yYw8tZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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