SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '801ca127b6f4ad1de4b7e8612adfc76794ed68fad24d8d1df319519a0a092d03' 
  AND token = 'TtCv43pa5ho/tjwOOaZYDPHq1BDfuTm/pV7alIlHGlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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