SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df10975c4ad63e8572594b9d6b96f851316537551154553054a18f07f83b874f' 
  AND token = '/hzmV1GXgvnUab6TsjEsem+AH9HvF4xewlv7WuFenkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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