SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb88224dc318828e8b6338ced9a5251d63c2b6cd2ff1e13531907c75eba95f1' 
  AND token = 'unxLcNcATF2tJzQSlLrTXMbwnPhKrSL9PLJC3LxKkhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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