SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ee64e8865536b1bbe06808eb2bbdfc6d0da3d13565a00c7b1681e86faa9889' 
  AND token = '7G5TQaKJ/MQA9jQYarJuxuSIjHztQK6CJnP+CN8ieho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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