SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e24126972776f342e27ed84ece028f0e78ac027275a10136ca446d72f1bf388d' 
  AND token = 'u93ewJhGvMbYEM7KU5L1och4hgAoa1BbuLYtwvjWxGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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