SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b6a8a208e97692ff1e9f51c0eddb16c2395c32b59932ae0249c1bdefec6ab14' 
  AND token = 'APm3EPtjpprvYVe3hBk836x8EAXlVyaJwuq5IV5Bbm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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