SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '354547304641b75fc59a045e70539d1eb0bea56acb5ab9122896241eb80925b9' 
  AND token = 'jy+ag+GGnmYE+SOD+LA3jT3/mQLKyvJvZWOU/8BP4ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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