SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '782f3909d631e040bc91e27a347f6e339de8645d9e6b13cb454c69c1392555ff' 
  AND token = '+lVX0YMKpWzKbthsfIX8BwJsSHMKo6rZ2vDaFXeiUps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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