SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b216dcf88cd6e140c2dbc7e3ad63f50b0189f8956c33b489e6b72231689530f' 
  AND token = 'xEu8mvGwFrR3HNOkSQ/Pp1gUk32gbaJAAJMBONRVLts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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