SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d237c65757066626ff13fec9a705a10caa5611f9db0e1fe4959bcb195c73578' 
  AND token = 'l6Bl+StWWaBxT7eP41JSVgMHOIr2tSl63eHqO6LyikM=' 
  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"
    }
  }
}