SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c6def9845122a58b1871e6801faa7b7b5b3bdd2434374853979b30d08676694' 
  AND token = 'lGqocTwrGNiavWUBllLvrsgYuC+8PyEV34FMTtC9bEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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