SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5783cd2986cabce43da48cd6936b7834a876d364a7dd547f969544b14206c135' 
  AND token = 'MjCdQZW/4EKI5B01kDBbqHYD1uyvhY/4isrqYJJBahA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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