SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1976d842df1fe89036db66d5fa371eead0c9211663ae46acaaee9c93774e1b95' 
  AND token = 'yiWse5rxVnOEywpRAxKkZOAsFWdq2gnJJA0XVJdsCrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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