SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffa7beb73794f46672d41b28c176c52971e046fb7d751203524b056c8ad6cade' 
  AND token = 't2Znnfa+/qUXDVanXx0v+EHBI7fDGFQqokgHC8OdzJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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