SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db253a8149071419839a43c6a303589b57b1943c2097f443be4a24c1fd44b9ee' 
  AND token = '7u11LbxKhyAW6s3I4oj8MyqOfbTNc4+t2A2fLwf4ClM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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