SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '49e06a8616491bc89faa6b6039d6cd189c64c37f436c6ea628dbf4d6a7b3ca21' 
  AND token = 'qOH0Slrgaey3VfXsPFawnddWI0HAEdjUW9ssB0FW9yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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