SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf14f891228d5d7bacb112706787d034bc073dc6ee505eb706ecd1b8cf75f53d' 
  AND token = 'xsg9GfTQO/xZ3kd/gtIHOPtGLu42lAOWoZpjlMj+jlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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