SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0c7eae92547ee4c142121bc1585e947ad1e786c5a9f87f07d34c55c055855b5b' 
  AND token = 'sBa3B2KdSdyfTmvVf3S9ihukNVCVvatFxN1cYTHmQy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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