SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d9288747e1dd1dd7555151aa2c7dafd7685166abb9984b424fb3c1d9837f810' 
  AND token = 'svVXpwE7DVyet1oHjn7KpFcmzrWrDYu2aFxRRJV9gMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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