SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e464209d097cb5f45414e9d7128120aef0b28a4d3735a41ef4f5d320908893d2' 
  AND token = 'RiUGuTfgTf//9kVY4HuTqMWZIo6ENGzfhOg9oNc/eS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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