SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b40fa433c385b34ed9f69885ab831168806cee65504dfc31eb5a283fdd25de52' 
  AND token = 'qlp9+ofXloOJ36+blcAvF2NLhyoJk+kfydtLl1qqG8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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