SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78e93c8e2a67141d73fccb2420e2fa27d641feafd7ddf4399bbe74a5442ed3bd' 
  AND token = 'L54JlG3YMpxWncg04IFRBRxCyPukvrf2/MReAkn/+Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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