SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'aa6921bdcd7fb093a36f795ee200ec8dc98290447c9b028ed9a12123255d0e7d' 
  AND token = 'ul/xEtkH/AdjzXYzuyiOlYgBnyLGo9wbGLYzheMJ1Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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