SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33dc77b7f9d094117038d465eb9171c334b1f66321fbe44903c0ce5b78209f92' 
  AND token = 'FAJKxCz8jQmaiWTr6Zd0OkjSYRbydGekkR79g8VwMo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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