SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08310169890e21a1c6d5a2f81c453708dec8506074cd63dc97655aade461c7ac' 
  AND token = 'gy/8CwsNTVwRK8a8X0sJZJboTu/cErUaeBD/aXXSQK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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