SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f9c763156085c4b2168458cdf4f4a6bf2456968e2a4623cc4d637e397ee8ed0' 
  AND token = 'yKjq86yvTzsiF41A3ZcA9x/pqoVVO5JRLFSGPyRKO1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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