SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02d9d6726d39576c88a2b1dc0da6f7f8a541b3e09e8cc2a1af9309f92e6f3529' 
  AND token = 'uUZ1h/BUKMYgTAgzq2/Y7GeQz0RAFlMjGHWKhNv9hkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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