SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9ab6521921fc9fc6935fcb04714ef604325af0afa3e247e96c5a7e6b4fdd2bc0' 
  AND token = '0iil2uPEYwrSIxCzGL5flL01nwGdkIUQB0rMTvOhFPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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