SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2012a9c6c7af42b5e9a515508289a036f303d8a2b5c77c98dcad518739d2342' 
  AND token = '3pFf+XSbG6uvdHecUBGJDuUQoZbuVbNOgN2+KbV3GjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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