SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cb200064dc8a899f4c88bcbcce1771f8b8fce77d61315156a683d2a994d5e84' 
  AND token = 'lylANUnWDIl141VaOZuMwLe32wOKmnqXRd5ogp6Mh3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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