SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8706483dc0a2c4452c5ed0a4b4984c95bfbe3f916de72ab9ef71a11a2838438b' 
  AND token = 'si2GpdctLcTzFx6pcHjKt4cc+kgRr97IbVjKtdqA8Lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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