SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b02a2c42f07526c753407d917b9cc9414c21f3885b36dbfda65121d6050efb3c' 
  AND token = '4prAN+t6lASTKiUwpxQgcYrX+SWpyhtorySKh6E/Iyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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