SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e11d61c113a4b51a0046f01a313915fe68c0468dc9bbe87dd65a1c64d8c845c' 
  AND token = 'W5WyZUHVXX4///1WFT+Wu2y/vTZwPiqY0PgLQzNOwB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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