SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '779883e2750e37d8c490c60faf71e0660fc5d799539391f4c3e218ba527604af' 
  AND token = 'jLg/bH7t2YOE82i9IK+bE1tYMW9I3dFl3m2IkhpYxKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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