SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c729210243f10358f9784331aad62e1ccc456de31f40f7afc92871cc54470b3d' 
  AND token = 'q04FngTU92hX986pzISawOFua/ujSgmCrjQ6Zaiv4qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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