SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73f04c38d8e5c08951393c80713da0663e6a07efbca1b5689fefa850fb14374f' 
  AND token = 'HvY4BEocvlw3V3IBLiiocx8XiaekXKTW9pLpxtfMXxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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