SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '259497ff471a437fcc7061ecf851f8eb6dc59fecb44a5b99a92531eb6f60e766' 
  AND token = 'oausosoQGdQcIHH3Jkt4BrA17wVqcVKP7Uh5tvp7JGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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