SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef46f5d3283dba97dbae4ef2e00f78c4231a3c27418172e22dff483999e9c96' 
  AND token = 'kisNbPTnezFPWCIif8C9GV9Eqqp/hrdOQuCvdAZbHv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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