SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '547d145db6ce83de9b7a4552ffdba7d9c6aafc590943766470958d114b0f5e66' 
  AND token = 'P6JwKbzM0oZlzg5fI6llQs/Fw+8BKdsDLNv/GWvodGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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