SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d7779b93d7b62889364619aef33656c4a66f5d6433c954113309833b81ba370' 
  AND token = 'PwRFLrmwOTmhsYtskmmm0RFd5/Q/9pQiygw5Iwef8hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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