SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '422798b023dd48f3ad3fcdeaec1e387450f5b630794b86cf883f797feed30a94' 
  AND token = 'KcSkG3ZO2n79Tw7lio5SCVAolUOgzpcdebiUDV4nigA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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