SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b86ac9fa73488b07f26fe75430423f855198b016eceaca04f3a072e52e6a452' 
  AND token = 'mUw+tOqu4ro1Z3WGih4a57uuKFJnwBO1TEsGNX+p/LI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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