SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '205d625990f241c99a428284c91bc47f85ba87e0939646c234186c472fa35cbf' 
  AND token = '8eSAtiwgXzeQpB2o1z6TErVzIoattdnpQfBugImPCZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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