SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46707fb9fb157b1397d37f8b179d6b7602c0f6989831a816920379c5946327db' 
  AND token = 'vaK1uUAzJyGe6TY/RBaAN17xdbrgTm1zFY75X0+QXZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}