SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c1e8dd058e1c1879255bad3ef367637d0e926a6fe7db9957194d37701f754ba' 
  AND token = 'yAyafSOdk51nvPtCPnOX0Nvi1IDIZLS5T65+qvdJ1wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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