SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '655e6c065c90e542b4fd4ebabdca8f909e2c65290e7e455586e2f9e046af52d6' 
  AND token = 'I1VznnyraZv0XFTfo7PqRjSv61A08rwg4wFyF30WwCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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