SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '318fc4882a8c155dbf708f012b827fb87c7d3f78edbff51c35292e2c5195870a' 
  AND token = 'uqiUo+7wHwMdRlIMSGQL4vasCuscQ6pnyRsxYI3QfFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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