SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8f0c440f91b74342d400e0dc4c0a6bc6af35a48142600b8f12d25db10fe1deb' 
  AND token = 'MWLttjtZLhDqMFmDsTM6gtqtWVt1xDmNXtacUgvPPnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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