SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '140377d676952d20accf94b6be1cec64f2e0257a6b3288090aaf6a15cec37a37' 
  AND token = 'XyWXMPqRisVc6q1X22y9UbD6b9QspYyIet2k5EWbLHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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