SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecb3a3ccdaa94fb555b10a28afc1903fb352d26804f53b76df726777c4360dd2' 
  AND token = 'Lz3UAp6PB0pQrouixsU/bINK7DF/omwhlmfTeqTjTaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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