SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41d673a14328e781e98453cec0286f325050a0ccb68c7e13e8b6870646ec351f' 
  AND token = 'InzeEWbl779HsgY9FW39yCpYrEPYfcCSKpsrZYSRhO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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