SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e879c7d96c4116f081fb7d902c35fca8a638dcddd49f19f26fc9022bdd2b4176' 
  AND token = 'OD1XVY8CD9TE8gsfUvcOnsZZrccXfvAhfQvw5Fc58xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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