SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afc90c332cf8aa0827a3f7304c08fa0885042a2ace49afb05da926d564832900' 
  AND token = 'D+9vf2DzM0PXYtVeyTzdJsan41Ol082+xF3CWIYVrvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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