SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c44b005f8fd086a4625be3bd8592f5122638695e8497513e65b12dc926697d3' 
  AND token = 'yvSsKUZv9sJQXAmco9aPIH1WAAOYNXAGqL9bSlPAmMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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