SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfea0ccd1873ab5214f9b4ac93bb42530ecc19bf9bfc6a9d8d2cebfb046969ea' 
  AND token = 'QaXUp4gMmwq6bGy558gn8sPIpYY1hmGUDc5ma1Fedyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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