SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e677b8bdd6e931640f2330e324fa2bbbfb8209b2946f5ff16480404f7da6631b' 
  AND token = 'z8SHrB85/AvU3y6sTTv4ova4BDnk9GJHtx35fONh828=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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