SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c5a0d80a87692683d3238d96628f9b517b7c5f761a09c0f6b248430cb509bba' 
  AND token = '2nTyXvTx+BgPvqVq1W13oWheINxpwR+pLu/KAt8XCJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}