SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bd98c5c2ecf2e68baff3cadf1fa610aee6bbb78fa7f87327e61a5467bde3a01' 
  AND token = 'hb780T9LxeaK12Xq8TTj8/1BRNagbrgBdVQTVjehGvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}