SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2170faa0cb4078440f61d724c3b3d8e3051013a3fcf16f643d588098d5dd7dc0' 
  AND token = 'CAiSFlaXqUOlnG27JJDFCqsjuUf5P5k/l0ZyVN9lGvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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