SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72b9343971d19c77648f0b5b75fee8a4af63fb98d0c304369190c53f9e60a46d' 
  AND token = 'r2Y1tmmrPaQfzSYYxA38sUNLPwBRmQkNbAeBmzxlCpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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