SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '52d340a59d25d3ab39404974efd876542343be940874a432e30a966f31b05a97' 
  AND token = 'hXC9cCEzTcTCjsIju4cOpFmpOvk7fdywauMvEjxdmHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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