SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '796e0c872b0af5ea6d6d20e5bde54a8b8e9c4443f99b1afec1ef0b7d25f5b833' 
  AND token = 'MNNyfJoowySNZlFf3ZOUDnb8EJTOs7IGyKpHxd8glHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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