SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5be8385a87ef7f5c42a10b41841f373d837834af5fc9a265b1478f111dff6df7' 
  AND token = 'BgIQ7YrKLeflb19crTbxbCUs0V/aTFTdm0Pl8yT9a1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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