SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff5f1bfef2d7d940929ef2b932fad0b62a4f92897691d0ca894c4119665c9d1' 
  AND token = '6kuL/ZOk3XcaDIZESTniKPJ0t1HUGeAOBfxMWg3rzTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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