SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec0da6d887208dada1eb979c2cc8fa88bda07fbbcffaf85827e3952d9ce9a52f' 
  AND token = 'Hy6MZ3qDWELfqZlXuO8Cu3MlQdtWchYcUa3IZF4Cu94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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