SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f30f730adefbc031dd4e1afb02117761c8b91ecf0423a47ebfa3593b44e7adca' 
  AND token = 'mxOSWgkE/3bndOcOAfJReUES9cubTQRN0uesp101g3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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