SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '081fe137e1fcc53d419612ac3da26489ac01937eff38b38c10fa591d706bdbce' 
  AND token = 'Mv7vzLO7OeXoSNcrZ/NusTuJa81ixp1aHDZarLqDnP4=' 
  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"
    }
  }
}