SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ea2eb691fd12b54fb33844823ae1e797438864748e6cb4a58ddbadb58dfbea8' 
  AND token = '9p0Qs9Wu2f6cVZn9Td15qVGayC/d8c54e+tgs1jymZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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