SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c1929b53d356048668035c41146ba05c2f27e1ff74aadee31b948d2c373aea4' 
  AND token = 'vXS446nBMoGTNzk8Bs39fvfSFELj064bx8MY3P/OR4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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