SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84bb0a2f4b5e7a6a202ce56099ed7043e5c7219cb601642d97573a64908bb106' 
  AND token = 'v6mvJbJ+Xh8xSPcfo1ZgCPDg+iwkNmoQUee8AkXd6WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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