SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef2c2a7b57704217b921d435b7ea0920b467f0d7c32e763129fc7b3ace9a56bf' 
  AND token = '9oXho9nYy2miOx8sRzIVRA6tZ9voudHkxjrOYBqgJtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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