SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d71d09db1cb576599ccdd31f37d581452143227c1b71b143c5b613b1da9846c' 
  AND token = 'L9burLTQ51CASydXoTEzAFiSinF/o82ib7gcHYWgQIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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