SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd801716ac32d7515d3ae2b8145842b6a37d494f2f873ee2d94e39404626f2473' 
  AND token = 'xgS9YqeSXeG7RVsvmFzYgwB1rJ0xb8oWFSwu+nMgQZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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