SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3834f65a0dca4648481d293366707fb8878f09487cbdfc234eb8b0ec180220c7' 
  AND token = 'USO8uEEl9HhzgiHViP9TXthodderlcvqIkocRZOOqTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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