SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a462af15291a3e6ff25bfdbfcda8384b9221761741b5d8e90090636b18958991' 
  AND token = 'sRWDnimbPDekwhu2ejxvC1/M7OE4IxtBPAKbT7u5Tz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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