SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6217597d97c8171de42dae68bb3f53b432acd789fe416e41ef01e93499520fd5' 
  AND token = 'hv9GxkIUi5Ve7VGUhWb+ky1+KGzVgltxw+nNIUv9B68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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