SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888d60d6af5ef8579c5353b5259c450a85bb4ba34d2b8532cd71f73c67f580cc' 
  AND token = 'Q7aIDNv0SvaBZ4D8HYNacAKMcUFot4f8P9dJzarZMVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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