SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53d161956dcd18b836ff2e3ac4083e156ddd80a56ff7f35b5ae88cee5a444f78' 
  AND token = 'etrD397HXydvjUL+aRVv2VFFu2XZVtYImGzBJNsXKn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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