SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '287abd437494c436722d7562bd6312662e182ee55c5e234983eb715a98102dd7' 
  AND token = 'h6lwiZhEw1oO/wQVuz3FRg0jCZQvqGtlZjwKoK7wm+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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