SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c0f30675df67d8893e98f898f3f8ca657ddf26ad543979badc43ab651fb0cee' 
  AND token = 'rT40rDuWLums6FvOhq0v3HioWYar5Gv3mjtr4ywq4us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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