SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '880d574a5e49cfb851a3551d9991637f5ed97d9dd5d390233bfb94c43030745e' 
  AND token = 'h3A8RGbMe8Pmge0TiXn8ps0M7Hm61UltWkBejaJgdeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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