SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '319c090d3a86e6e61b205ad591f6ba8ebc7072151895e87446ccfc78a6806d72' 
  AND token = 'Bv3zaXGKtOivozj4xd9FGwBITwHT8NSri/6MnvzwRLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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