SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c98a584c9071edff4598cb4e3901b3dfae2bf66ec0aad3691e3a7ecd1d01dbf2' 
  AND token = 'hxTh4tIDtQMyr+jf4aVkimpLabYkT8am+QonwTHzaCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00087

JSON explain

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