SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '608830fac35e23302e56d6c5e97cae2c732639745bf0016e85224eab5ab7b6ea' 
  AND token = 'q4rf2K9RfCXSyJJWQoV6Js/Ws4Dn9W6FN4hzgHczhqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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