SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e547280ffa3e0540498cebb94a65ff30d7477da6cc1c51fa98852f6df3602ab6' 
  AND token = 'OnEn2laCH9hdTPghVNSPeHwMpRiDvDlfZcGsiJaIsP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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